(Merge to M-51) Revise the shelf alignment locking mechanism.

ash/wm/window_animations.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/wm/window_animations.h"
 
 #include <math.h>
 #include <algorithm>
 #include <utility>
 #include <vector>
@@ skipping 450 matching lines @@
     return item_rect;
 
   // If both the icon width and height are 0, then there is no icon in the
   // launcher for |window|. If the launcher is auto hidden, one of the height or
   // width will be 0 but the position in the launcher and the major dimension
   // are still reported correctly and the window can be animated to the launcher
   // item's light bar.
   if (item_rect.width() != 0 || item_rect.height() != 0) {
     if (shelf->shelf_layout_manager()->visibility_state() == SHELF_AUTO_HIDE) {
       gfx::Rect shelf_bounds = shelf->shelf_widget()->GetWindowBoundsInScreen();
-      switch (shelf->alignment()) {
-        case SHELF_ALIGNMENT_BOTTOM:
-          item_rect.set_y(shelf_bounds.y());
-          break;
-        case SHELF_ALIGNMENT_LEFT:
-          item_rect.set_x(shelf_bounds.right());
-          break;
-        case SHELF_ALIGNMENT_RIGHT:
-          item_rect.set_x(shelf_bounds.x());
-          break;
-      }
+      if (shelf->alignment() == SHELF_ALIGNMENT_LEFT)
+        item_rect.set_x(shelf_bounds.right());
+      else if (shelf->alignment() == SHELF_ALIGNMENT_RIGHT)
+        item_rect.set_x(shelf_bounds.x());
+      else
+        item_rect.set_y(shelf_bounds.y());
       return item_rect;
     }
   }
 
   // Coming here, there is no visible icon of that shelf item and we zoom back
   // to the location of the application launcher (which is fixed as first item
   // of the shelf).
   gfx::Rect work_area =
       gfx::Screen::GetScreen()->GetDisplayNearestWindow(window).work_area();
   int ltr_adjusted_x = base::i18n::IsRTL() ? work_area.right() : work_area.x();
   return shelf->SelectValueForShelfAlignment(
       gfx::Rect(ltr_adjusted_x, work_area.bottom(), 0, 0),
       gfx::Rect(work_area.x(), work_area.y(), 0, 0),
       gfx::Rect(work_area.right(), work_area.y(), 0, 0));
 }
 
 }  // namespace ash